Electronic devices, such as mobile phones, personal digital assistants (“PDAs”), smartphones, laptops, netbooks, tablet computers, desktop computers, and various other handheld devices are performing at higher and higher levels. Electronic devices process more information than ever before, process information faster, and essentially provide an improved user experience. At the same time, electronic devices are generally becoming more compact over time, packing more components into smaller sized devices. This trend is particularly prominent with portable electronic devices. Moreover, a common theme with portable electronic devices is that users typically prefer devices that are compact and have a long battery life, which promotes simplified transporting of the device and ease of use in remote locations without requiring any connection to a power grid.
While users often prefer smaller devices with increased functionality and performance, there are some drawbacks to electronic devices of the prior art. The trend to make electronic devices more compact has caused high temperatures to be generated in smaller and smaller confined areas. As components are packed closer together, to fit into smaller device housings, there is less space for heat to dissipate from the components. Electronic components produce heat and infrared energy which are radiated from the components to their environment. If dissipated adequately, heat and infrared energy are not a problem for users of the electronic device. However, many electronic devices create an amount of heat and infrared energy that cannot always be dissipated adequately, which causes hot spots or warm areas on the device. This is particularly troublesome with portable electronic devices that are handled or carried by a user. These areas of noticeably increased temperature may be uncomfortable to users and might even be painful or harmful under certain circumstances. For example, a user may feel that a portable electronic device is uncomfortably warm when the device is in his hand, located by his ear, located in his pocket, or sitting on his lap.
The prior art methods of dealing with increased heat include various passive and active solutions. Passive solutions include heat distribution and throttling down performance or features of the electronic device. Heat distribution uses conduction of heat to various areas of the device, and can be used to maximize convective and radiated heat loss. By distributing the heat, the occurrence of hot spots is typically reduced, however, heat distribution is typically inadequate as the sole method of cooling the device.
Components in the electronic device can be throttled back or duty cycled to reduce their power consumption and associated heat generation. However, throttling back components decreases the performance of the device and/or reduces features available for the user to use. The decreased performance and features may be perceptible to the user and can deteriorate the user experience. Further, throttling devices down can add costs to the device, specifically, more expensive parts that are capable of throttling down and/or additional development time of the throttling protocol may be required.
Active solutions for removing heat include various cooling devices such as a fan, piezo vibrator, or Peltier cooler. Active solutions consume power, and thus, reduce battery time and/or overall efficiency of the device. Also, active solutions can have reliability issues, and may be an initial point of failure in a device that impedes a user's use of a device. For example, a cooling fan may become troublesome to a user, even while still cooling the device adequately, the cooling fan may produce noises that are unacceptable for using the device. Particularly for portable electronic devices, if an active solution uses significant amounts of power, reduced battery time may become a significant issue. A low battery life can seriously restrict a user's intended use of a device. Accordingly, using active solutions may require a larger capacity battery, which is typically more expensive and/or physically larger.
Accordingly, manufacturers of electronic devices face challenges in adequately cooling the devices and in prolonging battery life and/or increasing device efficiency. The prior art fails to provide a sufficient solution for the above described challenges.